Removal of metals and other nonhydrocarbons by hydrogenation



Sept. 13, 1960 1. v. D. FEAR 2,952,628

REMOVAL OF METALS AND OTHER NON-HYDROCARBONS BY HYDROGEINATION Filed June 26, 1957 Catalyst Hydrogenation Charge 16 Pf 4r Catalyst Product INVENTOR. JAMES VAN DYOK FEAR iz LAM. v

TTORNEY Patented Sept. 13, 1960 REMOVAL OF METALS AND OTHER NON- HYDROCARBONS BY HYDROGEN ATION James Van Dyck Fear, Media, Pa., assignor to Sun Oil Company, Philadelphia, Pa., a corporation of New Jersey Filed June 26, 1957, Ser. No. 668,184

4 Claims. (Cl. 208-251) This invention relates to a method for treating petroleum with hydrogen, and more particularly to a manner of obtaining increased catalyst life in such operation.

Various catalytic hydrogenation processes for the treatment of petroleum or fractions thereof are well known in the art. One such hydrogenation involves the treatment of lubricating oil under relatively mild hydrogenation conditions which bring about an improvement in the color of the lubricating oil without greatly affecting the hydrocarbon composition of the oil. Many other processes for hydrogenation of petroleum materials are also well known in the art.

Frequently the charge stock for the hydrogenation contains metallic compounds, e.g. sodium or vanadium compounds, etc., which are removed in part during the hydrogenation and accumulate in and deactivate the catalyst. Superior results are obtained according to the invention, in hydrogenating such stocks by passage through a bed of solid hydrogenation catalyst particles, by reducing the liquid hourly space velocity during the process. In this way, greater amounts of charge can be passed through a given amount of catalyst before the metals accumulate in amount so large as to prevent satisfactory further operation. According to the invention, the reduction in space velocity is obtainable Without any decrease in throughput of charge.

In the process of the invention, the hydrogenation charge is contacted with the catalyst at a relatively high space rate in an early stage of the hydrogenation. At the high space rate, the rate of accumulation of metal on the catalyst is low, while the extent of the desired hydrogenation reactions is sufiiciently high to produce a satisfactory product. As the process continues, the extent of the desired hydrogenation reactions gradually declines to a predetermined minimum acceptable level. At this time, according to the invention, the space rate is reduced during further contact of hydrogenation charge with the same catalyst. The reduction in space rate is obtained by using additional catalyst, so that the rate of throughput of charge need not be reduced.

In the process according to the invention, the liquid hourly space velocity in the early stage of the process is preferably within the approximate range from 1 to 5 volumes of liquid charge per volume of catalyst bed per hour, though any otherknown space rate can be employed. The lower space rate employed in a later stage of the process is preferably Within the approximate range from 0.25 to 0.75 times the space rate in the earlier stage.

The further contact at lower space rate may follow immediately after the early stage referred to previously. Alternatively the further contact may be separated from the early stage by an intervening period as subsequently described in which the charge stock is contacted with another portion of the hydrogenation catalyst. During the further contact at the lower space rate, the extent of hydrogenation is at least as high as the predetermined acceptable level mentioned above, and is usually considerably higher than that level. The rate of accumulation of metal in the hydrogenation catalyst is higher during the operation at lower space rate than in the preceding operation at the higher space rate.

Considering the total operation in the process according to the invention, an acceptable level of hydrogenation is obtained in all stages, and a relatively low rate of accumulation of metal is obtained in the first stage. As a result of this lower rate of metal accumulation, an increase in catalyst life is obtained over that in conventional operation involving the use of a relatively high space rate throughout the process.

In preferred operation according to the invention, two or more separate portions of hydrogenation catalyst are employed. The charge stock is first contacted with one portion of catalyst at a relatively high space rate. When the extent of hydrogenation has decreased to a predetermined level, the charge stock is then contacted with another portion of the hydrogenation catalyst, the use of the first portion being temporarily discontinued. The contact with the second portion is performed at a relatively high space rate. When the extent of hydrogenation in such contacting has decreased to the predetermined level, the charge stock is then divided into portions, one of which is contacted with the first portion of catalyst and another with the second portion of catalyst, the space rate in the respective contacts each being less than in the prior stages. The total amount of charge stock hydrogenated in unit time is the same as in the early stages, but the space rate is less as a result of the use of a greater amount of catalyst than in the earlier stages.

In another embodiment, the contacting in the later stage is performed without dividing the charge between the catalyst portions, but instead passing the charge in series through the catalyst portions. Here again, the amount of charge hydrogenated in unit time is the same as in the early stages, but the space rate is less because of the contact of the charge with more catalyst than in the earlier stages.

The attached drawing is a schematic flowsheet illus trating two embodiments of the invention.

In a first stage, 2X barrels of charge per hour are passed through bed .10 while bed 12 is idle. Valves 16 and 20 are open, valves 18 and 22 closed. In a second stage, 2X barrels per hour are passed through bed 12 while bed 10 is idle. Valve 18 is open, valve 16 closed. In a third stage, in one embodiment, X barrels per unit time are passed through each of beds 10 and 12 simultaneously. Valves 16, 18 and 20 are open, valve 22 closed. In the third stage, in another embodiment, 2X barrels per hour are passed in series through beds 10 and 12. Valves 16 and 22 are open, valves 18 and 20 closed. Any desired number of catalyst portions can be employed in either embodiment.

The invention will be further described with reference to one process in which a charge oil containing metallic compounds and also containing hydrogenatable nonhydrocarbon constituents is treated, but it is to be understood that the invention is applicable to any known process for such hydrogenation. The hydrogenation conditions which are employed in the process according to the invention can be any such conditions which are known in the art. The hydrogenation process will generally involve a net consumption of hydrogen, although the invention is also applicable to the autofining process wherein hydrogen for the process is obtained in the dehydrogenation of naphthene constituents of the charge stock. The invention does not reside in the use of any particular hydrogenation catalyst, nor in the use of any particular temperature or pressure conditions, but rather in the manner of contacting a hydrogenation charge stock containing metallic Contaminants with the catalyst.

The process, with regard to which the invention will be more fully described, involves hydrogenation of lubricating oil which has been contacted with a sulfonating agent to form sulfonates, and has been treated for removal of sulfonates from the products. The removal of sulfonates usually involves extraction of alkali metal soaps of sulfonic ,acids from the oil by contact with an aqueous alcohol extracting medium. It is frequently found that the oil produced in this manner has unsatisfactory color and color stability. Inorder to overcome this defect, the oil is contacted with hydrogen and a hydrogenation catalyst under conditions effective to hydrogenate nonhydrocarbon constituents responsible for the poor color and color stability. The charge stock generally contains small amounts of sodium compounds remaining therein after the treatment for removal of sulfonates. The hydrogenation is preferably carried out at a temperature in the approximate range from 450 F. to 700 F. and a hydrogen pressure within the approximate range from 150 to 500p.s.i.g. V a

' The following example illustrates the invention:

A furfural-extracted lubricating oil railinate having Saybolt Universal viscosity at 100 -F. of about 80 seconds and containing about 12% aromatic compounds is treated with 24 pounds of anhydrous S vapor per barrel of oil at about 165 F. The products are stripped with air to remove 80;, and S0 and settled to separate green acids. The sour oil is mixed with about 0.7 volume of aviation alkylate per volume of sour oil and settled to remove additional green acids. The decanted solution is contacted with aqueous alcoholic caustic soda solution to neutralize the oil-soluble sulfonic acids and extract the sulfonates. The alkylate solution of oil is separated from the aqueous layer containing the sulfonates and distilled to remove alkylate and recover as residue an oil containing about 0.09% sulfur by weight and about 20 p.p.m. of sodium.

' The optical density color of the oil at 525 millimicrons is about 40.

The oil is contacted in liquid phase with fresh 20% molybdenum disulfide on alumina catalyst under hydrobeen treated, about 0.0192 total pound of sodium per pound of catalyst have accumulated in the two beds. By way of contrast, in conventional operation involving the use of a single bed containing 8100 pounds of catalyst and a space rate of 2 from the beginning, the product contains about 3 p.p.m. of sodium on the average for the entire operation from the beginning, and about gen pressure of 400 p.s.i.g. at 550 F. at liquid hourly space velocity of 4 volumes per volume of catalyst bed per hour. The oil rate is 1000 barrels per unit time, and the volume (including voids) of the catalyst bed is about 58 cubic feet, the space rate therefore being 4. The

weight of the catalyst is about 4050 pounds. The product contains about 10 p.p.m. of sodium.

7 After the contacting with hydrogen as described above has been continued until 4050 barrels of charge have been passed through the catalyst bed, the OD. color of the product is about 5. After 12,150 barrels have been,

treated, the OD. color is about 10. To prevent further decline in product color, contacting of charge with this portion of catalyst is temporarily discontinued.

Additional amounts of the same charge are contacted under the same conditions with a second fresh portion of the same catalyst, the oil rate again being 1000 barrels per unit time and the volume of bed and weight of catalyst again being 58 cubic'feet and 4050 pounds respectively.

rels is about 5 and after treatment of 12,150 about 10.

The charge rate through the second catalyst bed is now reduced, to about 500 barrels per hour, and the contacting of charge with the first catalyst bed is resumed, another 500 barrels per unit time being passed through that bed. The space rate in each bed is now 2. The products obtained from each bed have sodium contents of about 3 p.p.m. and OD. colors of about 3. Up to 8100 or more additional barrels of charge are passed through ,each bed before the OD. color declines to above 10. i

vAfter 40,500 barrels of charge total tor bothbeds have The product contains about 10 p.p.m. of a sodium. The product color after treatment of 4050 bar- 0.0254 pound of sodium per pound of catalyst has accumulated after treatment of 40,500 barrels of charge.

In operation with 8100 pounds of catalyst at 2 space rate from the beginning, the QB. color after treatment of 8100 barrels is about 3, and after treatment of 24,300 barrels is also about 3. However, this superiority in color to that obtained in operation according to the invention is usually an unnecessary feature, a color of 10 being entirely satisfactory. Therefore, the increased catalyst life obtained according to the invention makes operation according the invention superior for commercial purposes. 7

In order to obtain optimum utilization and life of catalyst, it is essential to contact each of two separate catalyst portions with charge stock at relatively high space rate before employing the catalyst portions simultaneously at lower space rate. The optimum utilization and life are not obtained by' using one portion of catalyst at high space rate and then using that'port-ion and a second portion simultaneously at lowspace rate, unless the second portion has previously been used at high space rate.

The invention claimed is:

'1. Process for treating a petroleum charge stock with hydrogen which comprises: contacting said petroleum charge stock containing metallic contaminants and hydrogenatable nonhydrocarbons with a first portion of a solid hydrogenation catalyst under conditions for hydrogenation of said nonhydrocarbons including a space rate of from 1 to 5 volumes of hydrocarbonsper volume of catalyst bed per hour adapted to minimize'retention of said metallic contaminants on said catalyst; continuing said contacting at said space rate until, as a result of decline in the activity of said catalyst for hydrogenating said nonhydrocarbons, the extent of said hydrogenating substantially declines; contacting additional said charge stock with a second portion of said. solid hydrogenation catalyst under conditions for hydrogenation of said nonhydrocarbons including a space rate of from 1 to 5 volumes of hydrocarbons per volume of catalyst bed per hour adapted to minimize retention of said metallic contaminants on said catalyst; continuing the latter contacting until the extent of hydrogenation substantially declines; subsequently contacting additional said charge stock with said first portion and said second portion of said catalyst under conditions for hydrogenation of said nonhydrocarbons, the space rate being 0.25 to 0.75 times the first named space rate as a result of the use of both portions of catalyst, thereby to obtain at least as great an extent of hydrogenation asobtained at the conclusion of the previous contacting with either of said catalyst portions, the rate of deposition of metallic contaminants on said catalyst being less for the total operation than in operation at said lower space rate throughout.

2. Process according to claim 1 wherein, in a first period, a portion of charge stock is contacted with said first portion of catalyst, andin a second period additional charge stock is contacted with said second portion of 1 alyst, and in a .third period additional charge stock is contacted in series with said first portion and said second 3 to 5 volumes of liquid oil per volume of catalyst bed portion of catalyst. per hour, in the presence of molybdenum disulfide as 4. Process according to claim 1 wherein said charge hydrogenation catalyst.

stock is a lubricating oil which has been contacted with a sulfonating agent and subsequently separated from 5 References Clted m the file of fins patent sulfonates formed by the latter contact, and wherein the UNITED STATES PATENTS first named conditions of hydrogenation include tempera- 2,574,451 Porter et a1. Nov. 6, 1951 ture in the appproximate range from 250 F. to 700 R, 2,608,521 Hoog Aug. 26, 1952 pressure within the approximate range from 150 to 500 2,697,683 Engel et a1. Dec. 21, 1954 p.s.i.g., and space rate within the approximate range from 10 2,706,703 Porter Apr. 19, 1955 

1. PROCESS FOR TREATING A PETROLEUM CHARGE STOCK WITH HYDROGEN WHICH COMPRISES: CONTACTING SAID PETROLEUM CHARGE STOCK CONTAINING METALLIC CONTAMINANTS AND HYDROGENATABLE NONHYDROCARBONS WITH A FIRST PORTION OF A SOLID HYDROGENATION CATALYST UNDER CONDITIONS FOR HYDROGENATION OF SAID NONHYDROCARBONS INCOUDLIGN A SPACE RATE OF FROM 1 TO 5 VOLUMES OF HYDROCARBONS PER VOLUME OF CATALYST BED PER HOUR ADAPTED TO MINIMIZE RETENTION OF SAID METALLIC CONTAMINANTS ON SAID CATALYST, CONTINUING SAID CONTACTING AT SAID SPACE RATE UNTIL, AS A RESULT OF DECLININF IN THE ACTIVITY OF SAID CATALYST FOR HYDROGENATING SAID NONHYDROCARBONS, THE EXTENT OF SAID HYDROGENATING SUBSTANTIALLY DECLINES, CONTACTING ADDITIONAL SAID CHARGE STOCK WITH A SECOND PORTION OF SAID SOLID HYDROGENATION CATALYST UNDER CONDITIONS FOR HYDROGENATION OF SAID NONHYDROCARBONS INCLUDING A SPACE RATE OF FROM 1 TO 5 VOLUMES OF HYDROCARBONS PER VOLUME OF CATALYST BED PER 